In other words, the chsh command changes the shell of non-root users to something that will allow them to log in, otherwise they will always be kicked. you can also achieve this by editing the /etc/passwd file and manually changing the shell. But running the command line is better.
eg:
chsh -s /bin/bash andygray
(where andygray is my non-root user) Now I can run as root, the su command. Eg:
su - andygray
and now we are all happy
Cheers,
- Andy Gray